As that profound philosopher of a bygone era, Peter Brady, once said, when it's time to change, you've got to rearrange. Nobody is more aware of the wisdom behind those words (or the difficulties of adolescence that accompanied them) than 18-year-old Lindsay Lohan, who recently showed off the set of her film "Just My Luck" alongside some noticeable changes to the formula that has made her a household name.

"I have to admit," laughs the freckle-faced starlet, "I kind of feel a little trampy."

As Lindsay Lohan darts around the set of the upcoming movie, kissing any man she can find on the lips, one can't help but consider all that the paparazzi would make of such images. The innocent teenager from "Freaky Friday" and the naive transfer student of "Mean Girls" seem a million miles away, replaced instead by a character named Ashley in desperate need of a lip lock.

"My character is basically one of the luckiest girls in the world," explains Lohan, casually kicking back between takes in ripped jeans and Ugg boots. "She's younger, she's getting promotions where she works and everything just goes really well for her all the time. She doesn't realize how lucky she is and kind of loses appreciation for the fact that she's lucky. Then she loses all of her luck after kissing someone. She goes to this tarot-card reader at this party she's having, and basically, she has to go around Manhattan with pictures of all the guys she hired as dancers and find the guy that she kissed, to kiss him again and get her luck back."

In the scene she's taping today, Lohan bursts into a recording studio and plants the kind of lingering hello on a sound engineer's mouth that will strike envy in the hearts of most males between the ages of 14 and, say, 85.

"I don't think I realized [how much kissing there would be] when I read the script," she laughs. "I'd say to [director] Donald [Petrie], 'Do I have to do this now? Do I really have to kiss him?' Because it's very uncomfortable. But yes, I do. It's not like a kiss kiss though; it's more like a smooch. We have some scenes that are very 'Sex in the City.' "

It's all part of the master plan for a post-"Herbie" transformation into adulthood. "It's a romantic comedy," Lohan says. "It's the first movie that I've done like this."

When she isn't heading into Meg Ryan territory, Lohan is threatening to take the title of sexiest stumbler away from Sandra Bullock. "I go through a lot of things, getting electrocuted and a lot of silly stuff, a lot of physical comedy, which is fun," she says. "I had done that before, but not as much as I do in this."

As witnessed during a recent "Saturday Night Live" hosting gig and on the cover of every tabloid at your local market, the young star has lost a great deal of weight and dyed her hair blond. On the set of "Luck," she says that change and reinvention are inevitable. "I went through a phase when I was like, 'I need to go out, and that's what I want to do,' " she says of her partying days, insisting they're behind her. "I've kind of just become really over it, in a way. I've moved to a different agency, and I want to get into producing and learning about investing and that kind of stuff. There's some amazing scripts I've gotten, and we're working on the movie 'A Prairie Home Companion' with Meryl Streep."

Romantic comedies? Producing and investing? Exchanging dramatic dialogue opposite an Oscar winner? It might be time to kiss the old Lindsay Lohan goodbye.